Yokohama F Marinos midfielder Shunsuke Nakamura faces a short spell on the sidelines after suffering an ankle injury during the defeat to Shimizu S-Pulse at the weekend.
Nakamura sustained a badly bruised ankle after a first-half challenge from Shimizu midfielder Akihiro Hyodo and, while he tried to battle through the pain, he was forced to come off five minutes later.
"Shunsuke caught his foot on his man on the follow through," Yokohama coach Kazushi Kimura said in the Daily Yomiuri.
"It's a bruise. He's done the outside of his foot before, but now it's the inside. Looking the way he did, I didn't have much of a choice but to change him.
"What's troubling him most is his conditioning. I think he still has pain in his groin. It's not bad enough that he can't play with it, in which case he will because he personally doesn't want to lose his game instincts and match fitness."
Nakamura is now rated as doubtful for Japan's friendly against Serbia on Wednesday.